May 2, 2011 | 2
Even if one was allowed to make a volcano explode, creating the flows of interest looks impossible
In "Too Hard for Science?" I interview scientists about ideas they would love to explore that they don’t think could be investigated. For instance, they might involve machines beyond the realm of possibility, such as particle accelerators as big as the sun, or they might be completely unethical, such as lethal experiments involving people. This feature aims to look at the impossible dreams, the seemingly intractable problems in science. However, the question mark at the end of "Too Hard for Science?" suggests that nothing might be impossible.
The scientist: Greg Valentine, director of the Center for Geohazards Studies at the State University of New York, University at Buffalo.
The idea: The super-fast, searing hot avalanches of rock, ash and gas known as pyroclastic flows that volcanoes can disgorge are what destroyed and completely buried the ancient Roman cities of Pompeii and Herculaneum in 79 AD. They can move at speeds of at least 700 kilometers per hour and reach 800 degrees C in temperature — "they’re probably the most dangerous volcanic phenomenon," Valentine says.
Scientists have difficulty understanding how pyroclastic flows work, as the phenomena involved are very hard to scale down to a bench-top level. Learning more about these flows could help people survive them. "We know it can be impossible to outrun them, but it is possible for structures and possibly people to survive them, so if we can recreate their dynamics and understand where they might go around a given volcano, we might be able to create better emergency plans," Valentine says.
The problem: Even if scientists could experiment with a real volcano, it remains unclear how they could get it to let forth such torrents. Pyroclastic flows apparently result from complex interactions between gas bubbles traveling up a magma conduit and the surrounding material. To force a volcano to belch forth these flows, researchers would have to somehow get gases to seep up from the base of its magma conduit. One can’t drill a pipe into this conduit without the magma gushing out, and one can’t drop canisters of pressurized gas into the magma, as they would melt long before they reached the bottom.
The solution? To help solve mysteries regarding how volcanoes work, Valentine and his colleagues are developing a station where scientists from around the world can perform large-scale experiments simulating volcanic processes. "We’re now putting together designs for experiments and getting cost estimates," he says.
For instance, to simulate pyroclastic flows on a scale approaching reality, they would take a hopper full of hot particles and put in on top of a hill — basically, a bin on stilts whose bottom would empty out, creating plumes maybe 200 meters in diameter. "We would basically create a small volcano," Valentine says. "We could recreate all the important effects, take measurements of the flow and know the exact conditions that created it."
Image of Greg Valentine from the University of Buffalo.
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About the Author: Charles Q. Choi is a frequent contributor to Scientific American. His work has also appeared in The New York Times, Science, Nature, Wired, and LiveScience, among others. In his spare time he has traveled to all seven continents. Follow him on Twitter @cqchoi.
The views expressed are those of the author and are not necessarily those of Scientific American.
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